The invention generally relates to three-dimensional mechanical rock modeling and more particularly relates to high resolution rock property distribution as an integral part of three-dimensional mechanical earth modeling.
Three-dimensional (3-D) rock property modeling may be used to enhance 3D mechanical earth modeling (MEM) of oil or gas reservoirs. Such a model may be particularly useful in developing new and unconventional reservoirs, such as high pressure and high temperature (HPHT) fields, and/or fields which are highly faulted.
When used in time lapse analysis (also called “4-D analysis”), the 3-D MEM with enhanced property predictions supports better wellbore planning and formation integrity forecasting and may be used to characterize more correctly subsidence, compaction, damage to the cap rock integrity and fault sealing. It can also help to determine the maximum depletion and optimum production for a field when coupled to reservoir pressures and field stress developments.
Fields that are characterized by anisotropic rock properties, faults and sealing boundaries in the reservoir, are subjected to differential vertical and horizontal depletion in the reservoir layers during production. This may cause the horizontal principal stresses to deplete differentially, and thus rotate the stresses in space. The differential stress changes may be accompanied by deformation of the reservoir rocks and modified rock properties, which in turn may lead to such effects as rock failure if the rock strength is exceeded, subsidence, compaction, damage of the cap rock integrity, fault sealing, wellbore problems, and sand production. These problems may be avoided by characterizing rock properties with a high lateral and vertical resolution in an adequate 3-D MEM workflow.